Numerical analysis (Total 714696 Papers Found)

In the analysis of large random wireless networks, the underlying node distribution is almost ubiquitously assumed to be the homogeneous Poisson point process. In this paper, the node locations are assumed to form a Poisson clustered process on the plane. We derive the distributional properties of the interference and provide upper and lower bounds for its CCDF. We consider the probability of successful transmission in an interference limited channel when fading is modeled as Rayleigh. We provid ...
A new discretization concept for optimal control problems with control constraints is introduced which utilizes for the discretization of the control variable the relation between adjoint state and control. Its key feature is not to discretize the space of admissible controls but to implicitly utilize the first order optimality conditions and the discretization of the state and adjoint equations for the discretization of the control. For discrete controls obtained in this way an optimal error es ...
In initial value problems for ODEs with interval-valued parameters and/or initial values, it is desirable in many applications to be able to determine a validated enclosure of all possible solutions to the ODE system. Much work has been done for the case in which initial values are given by intervals, and there are available software packages that deal with this case. However, less work has been done on the case in which parameters are given by intervals. We describe here a new method for obtain ...
We describe the open-source tool dReal, an SMT solver for nonlinear formulas over the reals. The tool can handle various nonlinear real functions such as polynomials, trigonometric functions, exponential functions, etc. dReal implements the framework of δ-complete decision procedures: It returns either unsat or δ-sat on input formulas, where δ is a numerical error bound specified by the user. dReal also produces certificates of correctness for both δ-sat (a solution) and unsat answers (a pro ...
In this paper, the existence of limit cycles for the bilinear systems is investigated. Based on the differential and integral inequalities approach, not only the exponentially stable limit cycles phenomenon of such systems can be certified but also the oscillation behaviors of such systems can be accurately predicted. Finally, numerical simulations are provided to illustrate the feasibility and effectiveness of the obtained result. ...
Average consensus is a widely used algorithm for distributed computing and control, where all the agents in the network constantly communicate and update their states in order to achieve an agreement. This approach could result in an undesirable disclosure of information on the initial state of an agent to the other agents. In this paper, we propose a privacy preserving average consensus algorithm to guarantee the privacy of the initial state and asymptotic consensus on the exact average of the ...
This paper deals with typical problems that arise when using wavelets in numerical analysis applications. The rst part involves the construction of quadrature formulae for the calculation of inner products of smooth functions and scaling functions. Several types of quadratures are discussed and compared for diierent classes of wavelets. Since their construction using mono-mials is ill-conditioned, also a modiied, well-conditioned construction using Chebyshev polynomials is presented. The second ...
Let u and uV ∈ V be the solution and, respectively, the discrete solution of the non-homogeneous Dirichlet problem u = f onP, u|∂P = 0. For any m ∈ N and any bounded polygonal domain P, we provide a construction of a new sequence of finite dimensional subspaces Vn such that ‖u− uVn‖H 1 ≤ C dim(Vn)−m/2‖f ‖Hm−1 , where f ∈ Hm−1(P) is arbitrary and C is a constant that depends only on P and not on n (we do not assume u ∈ Hm+1(P)). The existence of such a sequence of subs ...
Massive MIMO systems are well-suited for mm-Wave communications, as large arrays can be built with reasonable form factors, and the high array gains enable reasonable coverage even for outdoor communications. One of the main obstacles for using such systems in frequency-division duplex mode, namely, the high overhead for the feedback of channel state information (CSI) to the transmitter, can be mitigated by the recently proposed joint spatial division and multiplexing (JSDM) algorithm. In this p ...
The study of the interaction of lightning electromagnetic fields with electrical systems and the design of appropriate protection strategies are generally based on statistical distributions of the lightning current measured at the channel base using either instrumented towers or artificial initiation of lightning using rockets. Recent studies based both on numerical modeling and experimental observations have shown that the presence of the structure struck by (or used to initiate) lightning does ...
This paper discusses the self-adaptive mechanisms of evolution strategies (ES) and real-coded genetic algorithms (RCGA) for optimization in continuous search spaces. For multi-membered evolution strategies, a self-adaptive mechanism of mutation parameters has been proposed by Schwefel. It introduces parameters such as standard deviations of the normal distribution for mutation into the genetic code and lets them evolve by selection as well as the decision variables. In the RCGA, crossover or rec ...
In order to cope with the relentless data tsunami in 5G wireless networks, current approaches such as acquiring new spectrum, deploying more BSs, and increasing nodes in mobile packet core networks are becoming ineffective in terms of scalability, cost and flexibility. In this regard, context- aware 5G networks with edge/cloud computing and exploitation of big data analytics can yield significant gains for mobile operators. In this article, proactive content caching in 5G wireless networks is in ...
This paper is concerned with the global exponential anti-synchronization of a class of chaotic memristive neural networks with time-varying delays. The dynamic analysis here employs results from the theory of differential equations with discontinuous right-hand side as introduced by Filippov. And by using differential inclusions theory, the Lyapunov functional method and the inequality technique, some new sufficient conditions ensuring exponential anti-synchronization of two chaotic delayed memr ...
In clearing terrains contaminated or potentially contaminated by landmines and/or unexploded ordnances (UXOs), a quick wide-area surveillance is often required. Nevertheless, the identification of dangerous areas (instead of the detection of each subsurface object) can be enough for some scenarios/applications, allowing a suitable level of security in a cost-saving way. In such a framework, this paper describes a probabilistic approach for the definition of risk maps. Starting from the measureme ...
We consider the problem of repairing a database that is inconsistent wrt a set of integrity constraints by updating numerical values. In particular, we concentrate on denial integrity constraints with numerical built-in predicates. So far research in this context has concentrated in computational complexity analysis. In this paper we focus on efficient approximation algorithms to obtain a database repair and we present an algorithm that runs in O(n log n) wrt the size of the database. Our experi ...
A single TCP connection with a time varying capacity bottleneck link is considered. The bottleneck capacity varies arbitrarily and independently of the TCP connection traffic; it aims at reproducing typical situations where capacity is modulated by exogenous process, such as wireless channel with link adaptation or bursty channels. The key point is to understand the interplay of the TCP congestion control evolution and the time constants of the bottleneck link capacity time variation. Fluid mode ...
Edge detection has traditionally been associated with detecting physical space jump discontinuities in one dimension, e.g. seismic signals, and two dimensions, e.g. digital images. Hence most of the research on edge detection algorithms is restricted to these contexts. High dimension edge detection can be of significant importance, however. For instance, stochastic variants of classical differential equations not only have variables in space/time dimensions, but additional dimensions are often i ...
  • Hui Wang,
  • IEEE Trans. Pattern Anal. Mach. Intell.
  • 2006
Finding nearest neighbors is a general idea that underlies many artificial intelligence tasks, including machine learning, data mining, natural language understanding, and information retrieval. This idea is explicitly used in the k-nearest neighbors algorithm (kNN), a popular classification method. In this paper, this idea is adopted in the development of a general methodology, neighborhood counting, for devising similarity functions. We turn our focus from neighbors to neighborhoods, a region ...
’bo new recursive factorizations are developed of the mass matrix for fixed-base and mobile-base manipulators. First, the mass matrix M is shown to have the factorization M = H$M$* H’. This is referred to here as the Newton-Euler factorization because it is closely related to the recursive Newton-Euler equations of motion. This factorization may be the simplest way to show the equivalence of recursive Newton-Euler and Lagrangian manipulator dynamics. Second, the mass matrix is shown to have ...
This article assumes two stages in the formation of the bones in the calvaria, the first one takes into account the formation of the primary centers of ossification. This step counts on the differentiation from mesenchymal cells into osteoblasts. A molecular mechanism is used based on a system of reaction-diffusion between two antagonistic molecules, which are BMP2 and Noggin. To this effect we used equations whose behavior allows finding Turing patterns that determine the location of the primar ...
A new hybrid two-step method for computation of P S V seismic motion at inhomogeneous viscoelastic topographic structure is presented. The method is based on a combination of the discrete-wavenumber (DW), finite-difference (FD), and finite-element (FE) methods. In the first step, the DW method is used to calculate the source radiation and wave propagation in the background 1D medium. In the second step, the FD-FE algorithm is used to compute the wave propagation along the topographic structure. ...
In this paper we examine some general features of the time-dependent dynamics of drop deformation and breakup a t low Reynolds numbers. The first aspect of our study is a detailed numerical investigation of the ‘ end-pinching ’ behaviour reported in a previous experimental study. The numerics illustrate the effects of viscosity ratio and initial drop shape on the relaxation and/or breakup of highly elongated droplets in an otherwise quiescent fluid. In addition, the numerical procedure is us ...
This paper presents a multidisciplinary design analysis method for permanent magnet (PM) motors with soft magnetic composite (SMC) cores. Firstly, a multidisciplinary design analysis process is investigated to evaluate the performance of these motors, which includes electromagnetic analysis (based on new core loss model), thermal analysis, and mechanical modal analysis. Then a lumped 3-D thermal network model is developed for the thermal analysis in the design process. Finally, to demonstrate th ...
Although femtocell deployments in residential buildings have been increasingly prevalent, femtocell deployment in commercial building environments remains in its infancy. One of the main challenges lies in the femtocell base stations (FBS) placement problem, which is complicated by the buildings' size, layout, structure, and floor/wall separations. In this paper, we investigate a joint FBS placement and power control optimization problem in commercial buildings with the aim to prolong mobile han ...
We study the problem of dynamic pricing, promotion and replenishment for a deteriorating item subject to the supplier’s trade credit and retailer’s promotional effort. In this paper we adopt a priceand time-dependent demand function to model the finite time horizon inventory for deteriorating items. The objective of this paper is to determine the optimal retail price, the promotional effort and the replenishment quantity so that the net profit is maximized. We discuss the properties and deve ...
The understanding of electrokinetic transport of fluid or particles in microchannel plays an important role in the design and the optimization of microand nanofluidic devices. Two important electrokinetic phenomena are electro-osmosis and electrophoresis. In order to study these phenomena, the lattice Boltzmann solver is coupled with the iteration solver for the Poisson equation. Using these numerical schemes, the transient behavior of the electro-osmotic flows is investigated for various physic ...
Stewart manipulator using genetic algorithm as an efficient search technique is investigated. Kinematics and dynamics models were introduced in detail for simulation purpose. A PD task space control scheme was used. For demonstrating technique feasibility, a Stewart manipulator numerical-model was built. A genetic algorithm was then employed to search for optimal controller gains. The controller was tested onsite a generic circular mission. The simulation results show that the technique is highl ...
Dynamic neural networks with different time-scales include the aspects of fast and slow phenomenons. Some applications require that the equilibrium points of these networks be stable. The objective of the paper is to develop sufficient conditions for stability of the dynamic neural networks with different time scales. Lyapunov function and singularly perturbed technique are combined to access several new stable properties of different time-scales neural networks. Exponential stability and asympt ...
We construct simple macrodynamic models with policy lag by means of mixed difference and differential equations, and study how lags in policy response affect the macroeconomic (in)stability. Local dynamics of the prototype model are studied analytically, and the global dynamics of the prototype and the extended models are studied by means of numerical simulations. We show that the government can stabilize the intrinsically unstable economy if the policy lag is sufficiently short, but the system ...
This paper considers a clustering problem where a given data set is partitioned into a certain number of natural and homogeneous subsets such that each subset is composed of elements similar to one another but di!erent from those of any other subset. For the clustering problem, a heuristic algorithm is exploited by combining the tabu search heuristic with two complementary functional procedures, called packing and releasing procedures. The algorithm is numerically tested for its e!ectiveness in ...
In this paper, we present a stable boundary element domain decomposition method to solve boundary value problems of the Helmholtz equation via a tearing and interconnecting approach. A possible non-uniqueness of the solution of local boundary value problems due to the appearance of local eigensolutions is resolved by using modified interface conditions of Robin type, which results in a Galerkin boundary element discretization which is robust for all local wave numbers. Numerical examples confirm ...
Quadratic stability of switched systems consisting of a class of m-discrete subsystems is studied. An interval matrix is constructed to transform the discrete-time switched system into interval system. Then, a sufficient condition is presented in terms of linear matrix inequality for the quadratic stability of discrete-time switched systems under arbitrary switching laws. This condition is much simpler than the other methods because it needs only one linear matrix inequality to solve. A numerica ...
Numerical addition theorems of both axially anisotropic and axially isotropic parallel-plate modes are derived using a method based on boundary integral equations. This leads to a generalized multiple scattering (GMS) method for signal/power integrity analysis of dense vias in an arbitrarily shaped plate pair, which overcomes the limitation of the conventional multiple scattering method depending on the analytical addition theorems in an infinitely large or a finite circular plate pair. Both the ...
We present a complete numerical algorithm of isolating all the real zeros of a zero-dimensional triangular polynomial system <i>F</i><sub>n</sub> Z[<i>x</i><sub>1</sub>…,<i>x</i><sub>n</sub>]. Our system <i>F</i><sub>n</sub> is general, with no further assumptions. In particular, our algorithm successfully treat multiple zeros directly in such systems. A key idea is to introduce evaluation bound ...
This paper presents failure analysis of solder joints with a damage-coupled viscoplastic model. A material model is developed to characterize the elasticity, plasticity, creep and damage of solder. A semiimplicit time-integration approach is adopted for the numerical implementation of the solder model. This solder model has been implemented into nite element codes developed at Sandia National Laboratories and into the commercial, nite element code ABAQUSTM with its user-de ned material subroutin ...
Recent studies have shown that both Mamdani-type and Takagi-Sugeno-type fuzzy systems are universal approximators in that they can uniformly approximate continuous functions defined on compact domains with arbitrarily high approximation accuracy. In this paper, we investigate necessary conditions for general multiple-input single-output (MISO) Mamdani fuzzy systems as universal approximators with as minimal system configuration as possible. The general MISO fuzzy systems employ almost arbitrary ...
Recently, a powerful separability criterion was introduced by O. Rudolf in [5] and by K. Chen et al. in [6] — basing on realignment of elements of density matrix. Composing the main idea behind the above criterion and the necessary and sufficient condition in terms of positive maps, we provide a characterization of separable states by means of linear contractions. The latter need not be positive maps. We extend the idea to multipartite systems, and find that, somewhat suprisingly, partial real ...
We present an iterative, non-overlapping domain decomposition method for solving the convection–diffusion equation. A reformulation of the problem leads to an equivalent problem, where the unknowns are on the boundary of the subdomains [F. Nataf, F. Rogier, E. de Sturler, in: A. Sequeira (Ed.), Navier–Stokes Equations on Related Nonlinear Analysis, Plenum Press, New York, 1995, pp. 307–377]. The solving of this interface problem by a Krylov type algorithm [Y. Saad, Iterative Methods for Sp ...
In this paper, we propose using Partial Differential Equation (PDE) techniques in wavelet based image processing to reduce edge artifacts generated by wavelet thresholding. We employ minimization techniques, in particular the minimization of total variation (TV), to modify the retained standard wavelet coefficients so that the reconstructed images have less oscillations near edges. Numerical experiments show that this approach improves the reconstructed image quality in wavelet compression and i ...
We present a fast shared memory multiprocessor with uniform memory access time. A rst prototype (SB{PRAM) is running with 4 processors, a 128 processor version is under construction. A second implementation (HPP) using latest VLSI technology and optical links shall run at a speed of 96 MHz. To achieve this speed, we rst investigate the redesign of ASICs and network links. We then balance processor speed and memory bandwidth by investigating the relation between local computation and global memor ...
This correspondence presents a sufficient condition for the existence, uniqueness, and global robust asymptotic stability of the equilibrium point for bidirectional associative memory neural networks with discrete time delays. The results impose constraint conditions on the network parameters of the neural system independently of the delay parameter, and they are applicable to all bounded continuous nonmonotonic neuron activation functions. Some numerical examples are given to compare our result ...
A comparative account of numerical chromosome variation in 2× and 4× callus cultures ofHyoscyamus muticus examined at monthly intervals reveals that both types of calli tend to attain a genomic flux around 4×. Parallels apparently exist between the course of ploidy change and chromosomal flow in culture and evolutionary processes in nature, suggesting the utility of the in vitro system as a rapid approach for recognizing trends in genome evolution. ...
We present results of the design, fabrication, and testing of a microfabricated, membrane-type magnetic actuator. Magnetic pieces made of electroplated Permalloy (Ni80Fe20) are embedded in a thin ̄exible membrane made of silicone elastomer. When an external magnetic ®eld is applied, a torque generated on the magnetic pieces produces membrane displacement. Permalloy pieces that are 100-mm-wide, 870mm-long, and 22-mm-thick are strategically positioned in a 2-mm-square, 40-mm-thick polydimethyls ...
In the mobile era, the demand for Internet connection for moving vehicles (such as cars, buses and subways) is growing fast. The Network Mobility (NEMO) basic support protocol (B-NEMO) was introduced to provide Internet access for a group of users in a moving vehicle in an effective manner. As an extension of Mobile IPv6 (MIPv6), B-NEMO inherits the limitations from both the host-based and the centralized mobility management protocol such as sub-optimal routing (especially, in the nested NEMO sc ...
Parcel Eulerian–Lagrangian Hamiltonian formulations have recently been used in structure-preserving numerical schemes, asymptotic calculations, and in alternative explanations of fluid parcel (in)stabilities. A parcel formulation describes the dynamics of one fluid parcel with a Lagrangian kinetic energy but an Eulerian potential evaluated at the parcel’s position. In this paper, we derive the geometric link between the parcel Eulerian–Lagrangian formulation and well-known variational and ...
Recent results indicate how to optimally schedule transmissions of a measurement to a remote estimator when there are limited uses of the communication channel available. The resulting optimal encoder and estimation policies solve an important problem in networked control systems when bandwidth is limited. Previous results were obtained only for scalar processes, and the previous work was unable to address questions regarding informational relevance. We extend the state of-the art by treating th ...
The effects of radiation reaction on the motion of charged particles are studied in strong electric and magnetic fields with special attention to the vacuum near-field region of an oblique rotator. For strong radiation damping a local velocity field is derived from the Lorentz-Dirac equation, which efficiently describes the motion of electrons and positrons in the whole range of typical pulsar parameters. The velocity field allows to define regions in the inner magnetosphere, where due to the ra ...
The Navier–Stokes equations arise naturally as a result of Ehrenfests’ coarse-graining in phase space after a period of free-flight dynamics. This point of view allows for a very flexible approach to the simulation of fluid flow for high-Reynolds number. We construct regularisers for lattice Boltzmann computational models. These regularisers are based on Ehrenfests’ coarse-graining idea and could be applied to schemes with either entropic or non-entropic quasiequilibria. We give a numerica ...
This paper aims at investigating the relationship between gestures’ expressivity and the amount of attention they attract. We present a technique for quantifying behavior saliency, here understood as the capacity to capture one’s attention, by the rarity of selected motion and gestural expressive features. This rarity index is based on the real-time computation of the occurrence probability of expressive motion features numerical values. Hence, the time instants that correspond to rare unusu ...
This paper extends and improves on the performance measures of the Single-Server Single Queue System with Multiple Phases. The extension results in a new Queuing System of MultiServer with Multiple Phases under the conditions of First Come First Served, infinite population source, Poisson arrivals and Erlang service time. Queuing properties such as expected total service time, its variance and some performance measures like the expected number of phases in the system, expected number of phases i ...